A self-impacting PDC drill bit

Abstract

This invention provides a self-impacting PDC drill bit, comprising: a main housing with an installation space inside; a drill bit body connected to the lower end of the main housing, with a through hole axially penetrating the drill bit body at its core; and an impact assembly arranged within the installation space, comprising a drive unit, an impact load generating unit, and an impact body for transmitting the impact load. The drive unit is capable of generating rotational power under the action of drilling fluid, and the impact body passes through the through hole and can slide along the through hole. The impact body is configured to include a connecting shaft for connecting the impact load generating unit and multiple impact wings formed at the ends of the connecting shaft. Multiple impact teeth are evenly distributed on the impact end faces of the impact wings. The impact assembly is capable of generating periodic impact loads under the action of the drive unit and the impact load generating unit, and transmitting them to the impact body, thereby causing the impact teeth to impact and break rock, creating an impact crater at the bottom of the well.

Description

Technical Field

[0001] This invention belongs to the field of drilling tool technology, and specifically relates to a self-impacting PDC drill bit. Background Technology

[0002] PDC (polycrystalline diamond composite) drill bits are commonly used drilling tools in the oil drilling industry. As drilling depth increases, drilling difficulty also increases, placing higher demands on drill bits. In high-hardness, highly abrasive formations, the poor stability of drill bits during drilling affects drilling efficiency and results.

[0003] To improve the mechanical drilling speed and lifespan of drill bits, existing PDC drill bits typically use axial or circumferential accelerator tools in conjunction with the PDC drill bit to achieve impact rock breaking. However, accelerator tools have complex structures, many connecting parts, poor reliability, and high operational requirements. When conventional PDC drill bits are used with the aforementioned accelerator tools, the cutting teeth of the PDC drill bit are easily impacted and fail under high-frequency vibration, resulting in insufficient drill bit strength, poor stability, and consequently insufficient attack power and short lifespan.

[0004] Conventional PDC drill bits have a large impact structure that occupies a significant amount of space, which is detrimental to the drill bit's structural design. Furthermore, the complex structure, numerous connecting parts, and poor reliability contribute to the problem. When drilling in hard formations, the cutting teeth face significant challenges in penetrating the rock, resulting in high energy consumption for rock breaking, high friction, and severe thermal wear. In addition, during drilling, the impact load and vibrations from the impact are directly transmitted to the PDC cutting teeth, severely reducing their service life. Summary of the Invention

[0005] To address the technical problems described above, this invention aims to provide a self-impacting PDC drill bit. This self-impacting PDC drill bit can utilize drilling fluid to generate a self-impact load, which can significantly reduce the difficulty of the cutting teeth penetrating the rock and the energy consumption for rock breaking. Furthermore, it can generate an impact pit at the bottom of the well during drilling, making the rock ridge at the bottom of the well smaller and discontinuous in the core impact area, greatly reducing the rock strength in this area, significantly increasing the mechanical rotation speed, and thus significantly improving the rock breaking efficiency when drilling in formations with high hardness.

[0006] To this end, the present invention provides a self-impacting PDC drill bit, comprising: a main housing having an installation space formed inside; a drill bit body connected to the lower end of the main housing, wherein a through hole is provided in the center of the drill bit body along the axial direction; and an impact assembly arranged in the installation space, comprising a drive unit, an impact load generating unit, and an impact body for transmitting the impact load, wherein the drive unit is capable of generating rotational power under the action of drilling fluid, and the impact body passes through the through hole and is capable of sliding along the through hole; wherein the impact body is configured to include a connecting shaft for connecting the impact load generating unit and a plurality of impact wings formed at the ends of the connecting shaft, wherein a plurality of impact teeth are evenly distributed on the impact end faces of the impact wings, and the impact assembly is capable of generating periodic impact loads under the action of the drive unit and the impact load generating unit, and transmitting them to the impact body, thereby causing the impact teeth to impact and break rock to create an impact crater at the bottom of the well.

[0007] In one embodiment, a plurality of the impact wings are evenly spaced apart circumferentially at the end of the connecting shaft.

[0008] In one embodiment, a plurality of locating pins are installed on the connecting shaft, the plurality of locating pins corresponding to the impact wing in the circumferential direction, and a plurality of directional grooves are provided on the inner wall surface of the through hole, the locating pins being adapted to be installed in the directional grooves.

[0009] In one embodiment, the drive unit includes an impeller and a flow guiding mechanism disposed at the upper end of the impeller, wherein the drilling fluid can form a jet under the action of the flow guiding mechanism and drive the impeller to rotate.

[0010] In one embodiment, the flow guiding mechanism includes a guide wheel shaft and a guide wheel fixedly mounted on the guide wheel shaft. The guide wheel is fixedly connected to the main housing, and the impeller is mounted on the guide wheel shaft via a bearing.

[0011] In one embodiment, the rotation direction of the guide wheel blades is set to be opposite to that of the impeller blades.

[0012] In one embodiment, the impact load generating unit includes a valve disc mechanism and an impact rod connected to the lower end of the valve disc mechanism, wherein the impact body is fixedly connected to the impact rod.

[0013] The valve disc mechanism includes a moving valve disc fixedly connected to the impeller and a stationary valve disc fixedly connected to the impact rod. The moving valve disc rotates with the impeller, causing the flow area of ​​the valve disc mechanism to change periodically, thereby generating an impact load and transmitting it to the impact body.

[0014] In one embodiment, eccentric through holes are provided on the moving valve disc and the stationary valve disc respectively, so that the flow area of ​​the valve disc mechanism changes periodically.

[0015] In one embodiment, the impact load generating unit further includes a reset mechanism sleeved on the impact rod, which includes an elastic element and a limiting stop sleeved on the impact rod.

[0016] The limiting stop is fixedly connected to the inner wall of the main housing, and the two ends of the elastic member abut against the static valve disc and the limiting stop, respectively.

[0017] In one embodiment, the limiting stop is configured as a cylinder with a central hole and a plurality of connecting holes for the flow of drilling fluid on the cylinder, the impact rod passing through the central hole and being able to slide along the central hole.

[0018] Compared with the prior art, the advantages of this application are:

[0019] In operation, the self-impacting PDC drill bit according to the present invention operates with the fixed cutting mechanism and the self-impacting mechanism on the impact body moving relatively independently, ensuring that the impact load does not adversely affect the self-impacting PDC drill bit. Compared with existing single roller cone-PDC hybrid drill bits, the self-impacting PDC drill bit has a simpler structure, fewer connecting parts, higher reliability, and its self-impacting structure occupies less space on the drill bit body, which is beneficial for the drill bit's structural design and greatly improves its lifespan. Simultaneously, the self-impacting PDC drill bit significantly reduces the difficulty of the cutting teeth penetrating the rock and the energy consumption for rock breaking, achieving higher rock breaking efficiency when drilling in hard formations. Because the cutting teeth consume less energy and generate less friction when cutting in areas with fracture pits, thermal wear is greatly reduced. Furthermore, the impact teeth can slide relative to the drill bit body in the direction of impact load transmission, preventing the impact load and vibration generated by the impact from being directly transmitted to the cutting teeth, thus extending their service life. Using the self-impacting PDC drill bit according to the present invention, an impact pit can be generated at the bottom of the well during drilling, which makes the small rock ridges generated by the cutting teeth discontinuous, especially the small annular rock ridges generated by the cutting teeth in the core area are effectively broken. This can significantly increase the mechanical speed, thereby greatly improving the rock breaking drilling efficiency of the self-impacting PDC drill bit and enhancing the rock breaking effect. Attached Figure Description

[0020] The invention will now be described with reference to the accompanying drawings.

[0021] Figure 1 The structure of the self-impacting PDC drill bit according to the present invention is schematically shown.

[0022] Figure 2The structure of the guide wheel is shown schematically.

[0023] Figure 3 The structure of the eccentric hole in the moving valve disc is schematically shown.

[0024] Figure 4 The structure of the impactor is shown schematically.

[0025] Figure 5 The structure of the impact end face of the impactor is schematically shown.

[0026] Figure 6 The structure of the drill bit body is shown schematically.

[0027] Figure 7 The diagram schematically shows the structure of the impactor mounted on the drill bit body.

[0028] In this application, all drawings are schematic and are used only to illustrate the principles of the invention, and are not drawn to scale. Detailed Implementation

[0029] The invention will now be described with reference to the accompanying drawings.

[0030] For ease of understanding, in this application, the end closest to the wellhead is defined as the upper end, upstream end, or similar terms, for example... Figure 1 The left end is defined as the end furthest from the wellhead, while the end furthest from the wellhead is defined as the lower end, downstream end, or similar terms, for example... Figure 1 The right end of the drill bit. Meanwhile, the direction along the length of the self-impacting PDC drill bit is referred to as the longitudinal direction, axial direction, or similar terminology, while the direction perpendicular to it is referred to as the transverse direction, radial direction, or similar terminology.

[0031] Figure 1 The structure of the self-impacting PDC drill bit 100 according to the present invention is schematically shown. (As shown) Figure 1 As shown, the self-impacting PDC drill bit 100 includes a main housing 1, an impact assembly 3, and a drill bit body 5. The main housing 1 is cylindrical, and an installation space 2 is formed inside the main housing 1. The drill bit body 5 is fixedly connected to the lower end of the main housing 1, and a through hole 53 extending axially through the drill bit body 5 is provided in the center of the drill bit body 5 (see...). Figure 6The impact assembly 3 is installed within the installation space 2. The impact assembly 3 includes a drive unit, an impact load generating unit, and an impact body 6 for transmitting the impact load. The drive unit generates rotational power under the action of drilling fluid. The impact body 6 passes through a through hole 53 and can slide along the through hole 53. The impact assembly 3 generates periodic impact loads under the action of the drive unit and the impact load generating unit, and transmits these loads to the impact body 6, enabling the impact body 6 to generate periodic impact loads to break rock. Thus, the self-impacting PDC drill bit 100 can create an impact crater at the bottom of the well during drilling.

[0032] In one embodiment, the upper end of the main housing 1 is configured as a threaded joint for connecting an upper drill rod (not shown).

[0033] According to the present invention, such as Figure 1 As shown, the drive unit includes an impeller 34 and a flow guiding mechanism 35 disposed at the upper end of the impeller 34. The drilling fluid can form a jet under the action of the flow guiding mechanism 35 and impact the impeller 34, thereby driving the impeller 34 to rotate. The flow guiding mechanism 35 includes a guide shaft 351 and a guide wheel 352 fixedly mounted on the guide shaft 351. The structure of the guide wheel 352 is as follows... Figure 2 As shown. In one embodiment, the guide wheel 352 is fixedly mounted on the guide wheel shaft 351 by threads. The guide wheel 352 is fixedly connected to the main housing 1. In one embodiment, the main housing 1 is provided with a pin hole, and the guide wheel 352 is provided with a mounting hole. After the pin hole is aligned with the mounting hole, a positioning pin 11 is installed, thereby forming a fixed connection between the guide wheel 352 and the main housing 1. Figure 2 The structure of the guide wheel 352 is shown schematically.

[0034] A guide wheel cap 353 is provided at the upper end of the guide wheel shaft 351 to guide the drilling fluid and facilitate the flow of the drilling fluid to the guide wheel 352.

[0035] Impeller 34 is mounted on guide wheel shaft 351 via bearings (not shown), forming a rotatable connection between impeller 34 and guide wheel shaft 351. Drilling fluid, under the action of guide wheel 352, forms a jet that impacts impeller 34, thereby driving impeller 34 to rotate. To enhance the impact of the fluid on the blades of impeller 34, the rotation direction of the blades of guide wheel 352 is set to be opposite to the rotation direction of the blades of impeller 34.

[0036] According to the present invention, such as Figure 1As shown, the impact load generating unit includes a valve disc mechanism 31 and an impact rod 32 connected to the lower end of the valve disc mechanism 31. The impact body 6 is fixedly connected to the impact rod 32. The valve disc mechanism 31 includes a moving valve disc 311 fixedly connected to the impeller 34 and a stationary valve disc 312 fixedly connected to the impact rod 32. The moving valve disc 311 rotates with the impeller 34, causing the flow area of ​​the valve disc mechanism 31 to change periodically, thereby generating an impact load and transmitting it to the impact body 6. The stationary valve disc 312 is fixedly connected to the upper end of the impact rod 32. Preferably, the stationary valve disc 312 and the impact rod 32 are integrated, which not only facilitates processing and installation but also facilitates the transmission of impact load.

[0037] The impact load generating unit also includes a reset mechanism 33 sleeved on the impact rod 32. The reset mechanism 33 includes an elastic element 331 and a limiting stop 332 sleeved on the impact rod 32. The elastic element 331 can be, for example, a spring. The limiting stop 332 is fixedly connected to the inner wall of the main housing 1, and the two ends of the elastic element 331 abut against the static valve disc 312 and the limiting stop 332, respectively. The limiting stop 332 is constructed as a cylinder with a central hole, and multiple connecting holes 3321 for drilling fluid flow are provided on the cylinder. The impact rod 32 passes through the central hole and can slide along the central hole.

[0038] According to the present invention, eccentric through holes 310 are respectively provided on the moving valve disc 311 and the stationary valve disc 312 to make the flow area of ​​the valve disc mechanism 31 change periodically. Preferably, as shown in the figure... Figure 3 As shown, the eccentric through hole 310 can be constructed as a crescent-shaped through hole.

[0039] In this embodiment, the eccentric through holes 310 on the moving valve disc 311 and the stationary valve disc 312 are constructed as crescent-shaped through holes with the same shape and size. When the impeller 34 drives the moving valve disc 311 to rotate, the flow area of ​​the valve disc mechanism 312 changes periodically. When the two eccentric through holes 310 are not aligned (partially overlapping), a water hammer effect is formed between the moving valve disc 311 and the stationary valve disc 312, thereby generating an impact load. The impact load impacts the stationary valve disc 312, driving the impact rod 32 to overcome the resistance of the reset mechanism 33 and impact the rock. As the moving valve disc 311 rotates, when the positions of the two eccentric through holes 310 are aligned (completely overlapping), the fluid pressure is released, the water hammer effect disappears, and the stationary valve disc 312 and the impact rod 32 rebound under the action of the reset mechanism 33, starting the next cycle. Thus, the impact rod 32 can drive the impact body 6 to reciprocate axially under the action of the impact load and the reset mechanism 33, thereby causing the impact body 6 to impact and break the rock.

[0040] In one embodiment, the impeller 34 and the moving valve disc 311 are fixedly connected by threads. Preferably, the direction of the threads between the impeller 34 and the moving valve disc 311 is opposite to the direction of movement of the impeller 34, which can prevent the impeller 34 and the moving valve disc 311 from falling off during operation.

[0041] According to the present invention, the self-impacting PDC drill bit 100 can adjust the impeller 34 and guide wheel 352 with different helix angles according to different rock formations before going down into the well, so as to adjust the rotation speed of the impeller 34, thereby adjusting the impact frequency of the impact body 6, improving the applicability of the self-impacting PDC drill bit 100, which is very beneficial to improving rock breaking efficiency.

[0042] According to the present invention, such as Figure 4 As shown, the impact body 6 is configured to include a connecting shaft 61 for connecting the impact load generating unit and a plurality of impact wings 62 formed at the ends of the connecting shaft 61. A plurality of impact teeth 63 are evenly distributed on the impact end face (lower end face) of the impact wing 62. The impact assembly 3 can generate periodic impact loads under the action of the driving unit and the impact load generating unit, and transmit them to the impact body 6, so that the impact body 6 can generate periodic impact loads, thereby causing the impact teeth 63 to impact and break rocks.

[0043] The connecting shaft 61 of the impact body 6 is configured to extend a certain length axially, and a connecting part is provided at the upper end of the connecting shaft 61. The upper end of the connecting shaft 61 extends upward into the mounting space 2 and is fixedly connected to the impact rod 32 through the connecting part. A plurality of impact wings 62 are formed on the outer peripheral surface of the lower end of the connecting shaft 61 and are evenly spaced apart circumferentially. The lower end face of the impact wing 62 is formed as an impact end face, and a plurality of impact teeth 63 are evenly distributed on the impact end face of the impact wing 62. Figure 5 The structure of the impact wing 62 and impact tooth 63 is shown schematically.

[0044] like Figure 4 As shown, multiple locating pins 7 are installed on the connecting shaft 62, and these locating pins 7 correspond to the impact wing 62 in the circumferential direction. Meanwhile, as... Figure 6 As shown, multiple directional grooves 8 are provided on the inner wall surface of the through hole 53 in the core of the drill bit body 5. The multiple directional grooves 8 are evenly distributed in the circumferential direction and extend along the axial direction. The positioning pin 7 is adapted to be installed in the directional groove 8, and as the impact body 6 reciprocates axially, the positioning pin 7 slides along the directional groove 8 to orient the impact body 6, effectively preventing the impact body 6 from rotating.

[0045] like Figure 7As shown, the drill bit body 5 is provided with multiple main blades 51, which are evenly spaced circumferentially. Multiple cutting teeth 52 are evenly arranged on each main blade 51. The main blades 51 and cutting teeth 52 form a fixed cutting mechanism for the self-impacting PDC drill bit 100. The number of impact wings 62 on the impact body 6 is preferably equal to the number of main blades 51, and the impact wings 62 are positioned circumferentially between adjacent main blades 51. The impact wings 62 and impact teeth 63 on the impact body 6 form a self-impacting mechanism for the self-impacting PDC drill bit 100.

[0046] During operation, the self-impacting PDC drill bit 100 according to the present invention operates with the fixed cutting mechanism and the self-impacting mechanism on the impact body 6 moving relatively independently, and the impact load will not adversely affect the self-impacting PDC drill bit 100. Compared with the existing single roller cone-PDC hybrid drill bit, the self-impacting PDC drill bit 100 has a simple structure, fewer connecting parts, and high reliability. Furthermore, its self-impacting structure occupies less space on the drill bit body 5, which is beneficial for the drill bit's structural design and greatly improves its lifespan. Simultaneously, the self-impacting PDC drill bit 100 can significantly reduce the difficulty of the cutting teeth 52 penetrating the rock and reduce rock-breaking energy consumption, achieving higher rock-breaking efficiency when drilling in hard formations. Because the cutting teeth 52 consume less energy and generate less friction when cutting in areas with fracture pits, thermal wear is greatly reduced. In addition, the impact teeth 63 can slide relative to the drill bit body 5 in the direction of impact load transmission, preventing the impact load and vibration caused by the impact from being directly transmitted to the cutting teeth 52, which helps extend the service life of the cutting teeth 52.

[0047] The self-impacting PDC drill bit 100 of the present invention can generate an impact pit at the bottom of the well during drilling, which discontinuously breaks the micro rock ridges generated by the cutting teeth 52, especially effectively breaking the micro annular rock ridges generated by the cutting teeth in the core region. Compared with the bottom of the well formed by a conventional PDC drill bit, the bottom rock ridges of the self-impacting PDC drill bit 100 of the present invention are smaller and discontinuous in the area where the impact teeth 63 impact the rock, resulting in weaker rock in this area, which is broken before the micro rock ridges are fully formed. This allows the self-impacting PDC drill bit 100 of the present invention to significantly increase the mechanical rotation speed under the same drilling conditions, thereby greatly improving the rock-breaking drilling efficiency of the self-impacting PDC drill bit 100 and enhancing the rock-breaking effect.

[0048] In the description of this invention, it should be understood that the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0049] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0050] Furthermore, in the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0051] Finally, it should be noted that the above description is merely a preferred embodiment of the present invention and does not constitute any limitation on the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A self-impacting PDC drill bit, comprising: The main housing (1) has an installation space (2) formed inside it; A drill bit body (5) is connected to the lower end of the main housing, and a through hole (53) is provided in the center of the drill bit body (5) extending axially through the drill bit body (5); and An impact assembly (3) arranged within the mounting space (2) includes a drive unit, an impact load generating unit, and An impactor (6) for transmitting impact loads, the drive unit is capable of generating rotational power under the action of drilling fluid, the impactor (6) passes through the through hole (53) and is capable of sliding along the through hole (53); The impact body (6) is configured to include a connecting shaft (61) for connecting the impact load generating unit and a plurality of impact wings (62) formed at the ends of the connecting shaft (61). A plurality of impact teeth (63) are evenly distributed on the impact end faces of the impact wings (62). The impact assembly can generate periodic impact loads under the action of the driving unit and the impact load generating unit, and transmit these loads to the impact body, thereby causing the impact teeth (63) to impact and break rock, creating an impact crater at the bottom of the well. Multiple positioning pins (7) are installed on the connecting shaft, and the multiple positioning pins (7) correspond to the impact wing (62) in the circumferential direction. Multiple directional grooves (8) are provided on the inner wall surface of the through hole (53), and the positioning pins (7) are adapted to be installed in the directional grooves (8). The drive unit includes an impeller (34) and a flow guiding mechanism (35) disposed at the upper end of the impeller (34). The drilling fluid can form a jet under the action of the flow guiding mechanism (35) and drive the impeller (34) to rotate. The flow guiding mechanism (35) includes a guide wheel shaft (351) and a guide wheel (352) fixedly mounted on the guide wheel shaft (351). The guide wheel (352) is fixedly connected to the main housing (1). The impeller (34) is mounted on the guide wheel shaft (351) via bearings. The impact load generating unit includes a valve disc mechanism (31) and an impact rod (32) connected to the lower end of the valve disc mechanism (31). The impact body (6) is fixedly connected to the impact rod (32). The valve disc mechanism (31) includes a moving valve disc (311) fixedly connected to the impeller (34) and a stationary valve disc (312) fixedly connected to the impact rod (32). The moving valve disc (311) rotates with the impeller (34), causing the flow area of ​​the valve disc mechanism (31) to change periodically, thereby generating an impact load and transmitting it to the impact body (6). Eccentric through holes (310) are provided on the moving valve disc (311) and the stationary valve disc (312) respectively, so that the flow area of ​​the valve disc mechanism (31) changes periodically. The impact load generating unit also includes a reset mechanism (33) sleeved on the impact rod (32), which includes an elastic element (331) and a limiting stop (332) sleeved on the impact rod (32). The limiting stop (332) is fixedly connected to the inner wall of the main housing (1). The two ends of the elastic element (331) abut against the static valve disc (312) and the limiting stop (332) respectively.

2. The self-impacting PDC drill bit according to claim 1, characterized in that, Multiple impact wings (62) are evenly spaced apart circumferentially at the end of the connecting shaft (61).

3. The self-impacting PDC drill bit according to claim 1, characterized in that, The direction of rotation of the blades of the guide wheel (352) is set to be opposite to that of the blades of the impeller (34).

4. The self-impacting PDC drill bit according to claim 1, characterized in that, The limiting stop (332) is constructed as a cylinder with a central hole, and a plurality of connecting holes (3321) for drilling fluid to flow through the cylinder are provided on the cylinder. The impact rod (32) passes through the central hole and can slide along the central hole.

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